PARK Avenue bumped up against Bedford-Stuyvesant yesterday. And Harlem. And The Bronx. And even Detroit.

From 4 in the morning, the avenue whose name is synonymous with money, where it doesn’t take a sign to tell outsiders “Keep Out,” was awash with faces of black and brown.

People to whom the 10021 ZIP code means nothing, who spend summers on blacktop instead of Hamptons beaches, gathered to say goodbye to Aaliyah.

Park Avenue had never seen anything like this. On a street of forbidding limestone apartment buildings, where a pedestrian can be as rare a sight as a 1979 Ford Escort, people were singing. They prayed and they clapped. They even cheered.

Maybe I’m a trouble-maker, but I found it delicious to see the uptight, old denizens of New York’s petting zoo for the wealthy come face-to-face with a population they take great pains to avoid. They had to deal with it, and perhaps, secretly enjoy it.

Viola Borden, who came from Harlem in a wheelchair, found Park Avenue a suitable place to see Aaliyah off.

“She deserves to go out with the best,” Borden said. “Her fans were able to find her, even here!”

Monique and Sheaese Brannon, 24-year-old twins clad in identical zebra-stripe blouses, met Aaliyah six years ago when they were extras in her video. “She reminds us of how we are,” said Monique.

They joined a crowd lobbing cheers across the street at the celebs exiting St. Ignatius Church, the staid institution where Jacqueline Kennedy was eulogized.

“Hey Gladys – there’s Gladys Knight!” “Jay-Z! We love you!”

At one point, a tourist bus passed. The Germans inside waved frantically. And we waved back.

For a few, the scene did not go over well.

“They don’t live here,” kvetched one local.

“My neighbor was having a fit trying to get to the country – she couldn’t get her car out because of all this,” she said, pointing to the double-parked limos.

But the woman, who did not want to be identified, lingered for a long while on the street, just watching.

It took a tragedy to bring these unlikely strangers together, in peace. We may never see anything like this again.